Visting BRAZIL 12/2012-01/2013;where&how to travel (Rio de Janeiro)

I am travelling to Brasil between middle of December Protected content middle of January Protected content .Although I will be arriving (14.12. Protected content departing back home (12.012. Protected content Sao Paulo, where I will spend aprox. 1 week, I have set also Rio as the place to be during NYE. I would like to know which other places (i.e. Salvador in the North, Florianopolis in the South) I should/could visit in between, how long these stays could be (if there's not that much to see) and which would be then the best sequence to travel, considering my start in SP and my stay during NYE in Rio. What about places like Fortaleza or Santos? Which would be your TOP5-Brazilian destinations?Any other hints on domestic low-cost carriers will be also highly appreciated.